Abstract
The introduction of copper as wire bonding material brings about a new challenge of aluminum bond pad bimetallic corrosion at the copper/aluminum galvanic interface. Aluminum is well known to undergo pitting corrosion under halide-contaminated environments, even in slightly acidic conditions. This paper aims to study the corrosion morphology and progression of aluminum influenced by different halide contaminations in the presence and absence of galvanic contact with copper. We used a new corrosion characterization platform of the micropattern corrosion screening to simulate the copper wire bonding on the aluminum bond pad. The corrosion screening data and subsequent SEM–EDX analyses showed a striking difference in morphology and progression between chloride-induced and fluoride-induced aluminum corrosion. The corrosion products formed play a vital role in the resulting morphology and in sustaining further aluminum corrosion.
Highlights
Our day-to-day life extensively uses wire-bonded electronic devices (WBDs) for various applications in medicine, communication, transportation, and so on
This study focuses on the corrosion morphology and proposes F− contaminant mechanism related to WBD and compares them with Cl− contaminant corrosion
Al surface oxide is well known to form a series of complexes with F− ions ranging from AlF2+ to AlF63− [22] and reported literature shows that the adsorption of F− by Al oxide is maximum at pH 5 [23]
Summary
Our day-to-day life extensively uses wire-bonded electronic devices (WBDs) for various applications in medicine, communication, transportation, and so on. The cost-effective nature of wire-bonded devices rises due to their flexible interconnect assembly technology. Cu wiring has introduced reliability issues, such as corrosion of the aluminum (Al) bond pad, leading to WBD failure. Halides such as chloride (Cl−) and fluoride (F−) can corrode Al even at low ppm concentrations, causing the Cu wire to lift off from the Al pad [2,3,4,5]. The Cl− contaminant in packaging is usually from epoxy molding compounds (EMCs), which can initiate corrosion in the presence of moisture. F− contaminants mainly come from plasma processes, leading to non-stick-on-pad (NSOP) reliability issues [6]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call